We propose a TCMS based architecture of GALS NoCs based on the GigaNoC approach, a scalable NoC featuring packet-switched wormhole routing. At a clock frequency of 750 MHz a link bandwidth of up to 6 GByte/s is achieved. The resource efficiency of mesochronous and asynchronous communication links is analyzed. The asynchronous coupling of the PE to the switch boxes is evaluated. This allows for multi-voltage/multi-frequency scenarios, where the performance of each PE is adapted to the current performance requirements. TCMS-based communication links and asynchronously coupled PEs allow for the high efficiency of GALS-based NoCs with moderate additional resource requirements.